I think of SocialMedian as Digg's feisty little brother because it allows you to import your Digg submissions and, thus, in a sense, is like the little brother that copies what the big brother says but also has more to say. SocialMedian is more than that so I analyzed it in more depth...
Differences between Digg and SocialMedian
Like Digg, SocialMedian is a social news sharing site where users submit what they consider to be interesting news articles and blog posts. Popular submissions are voted to the top of the list for all to see. Unlike Digg and more like Twitter, SocialMedian encourages strangers with similar interests to follow each other stories; "newsmaker" is SocialMedian's term for people whose submitted stories you subscribe to. Theoretically, SocialMedian provides a more personlized news viewing experience than does Digg. However, from a competitive standpoint, Digg could probably implement SocialMedian's features pretty easily.
Things I like About SocialMedian
My favorite feature is the ability to configure SocialMedian to automatically import your Digg submissions. This allows me to digg something once and have it recorded on two news sites. In addition, SocialMedian can be configured to automatically clip posts from your blog. This automation allows you to spend more time voting for other peoples submissions because you spend less time submitting your discovered content. Even though the aforementioned automation increases the amount of content on SocialMedian, the automation can reduce the need for users to visit SocialMedian's site. In sum, these features are great for blog marketing because they can increase a blog's exposure with little ongoing work.
SocialMedian's Election Coverage
Yesterday, SocialMedian launched an Election 2008 News Feed. Digg also has a an election news feed but SocialMedian's election news feed is populated automatically from its users accounts on Twitter, Flickr, Facebook, MySpace, and YouTube; along side user blog posts and user submitted stories. Currently, Digg has more interesting submissions but that is expected since its user base is exponentially larger. In sum, SocialMedian is worth checking out because it provides an opportunity to interact with others with similar interests, as opposed to getting lost in Digg's mammoth user base.